VSS speed sensor lead for avc-r w/o factory ecu

[islandigital]

hey all,

I have a avc-r and i would like to connect it to the VSS in the 1g. I realaize its in the cluster but im having 2 issues...

1- the vehicle runs a stand alone engine management and is not using the factory harness (harnes has been hacked out by previous owner/idiot) so i need to know the pin where i can tap it direct from the back of the cluster

2-since the factory ecu is gone and not hooked up i dont know what type of output the vss is or its required input if nessaccary. i know its 4 "pulses" per cable revolution but is it neagative, positive and at what voltage/amparage?

I did, when i originally when to install the boost controler, found the reed switch but everything at the time that i tried did not work for the vss in on the avc-r. a little help would be appreceated. Thanks

 

[steve]

Look and see if it's still on pin 11 of the DLC. It's a signal that goes from battery voltage to ground as the VSS pulses.

Steve

 

[islandigital]

If i rember correctly there was only 2 wires going to that reed, from memory, I could see it going from 12v to neutral but how can it go to ground with only 1 input?

Do you have a pic for the # 11 pin? or is it numbered on the cluster?

 

[steve]

In DC circuits WTF is neutral?
One side of the reed switch is is connected to the ECU and pin 11 on the DLC the other is connected to ground. Normally the ECU provides a 12v bias on the wire that the switch pulls to ground to generate the pulses. Since you no longer have a stock ECU you need to check if the DLC pin 11 is still connected to the switch and then you can bias it yourself to whatever level you need.

Steve

 

[islandigital]

well when you say "bias" are you meaning run 12v to it? What i dont understand is you say that it has 12v on it then runs a ground pulse to it. Is that not creating a dead short in the system?

When i said "neutral" it was lack for a better term for disconeccting the signal, If in fact the backside of the cluster to the reed terminal (pin 11 dlc, Im not shure what the dlc is) sees ground then it would be....

ground................................ground..............................ground...........................ground

but your saying the ecu provided 12v to the wire so in essence it would be ...

ground-12v----------------ground-12v---------------------ground-12v-----------------ground-12v

Thats where im getting confused, as soon as that 12v wire sees that ground it will short, or is the reed switch set up so that it will not have any ill effects? Thanks for all of your help thusfar. Im glad im getting knoldegable responses.

 

[steve]

well when you say "bias" are you meaning run 12v to it? What i dont understand is you say that it has 12v on it then runs a ground pulse to it. Is that not creating a dead short in the system?

It would be it you did it that way and just connected the wire to 12v. The reed switch would last a microsecond or so and then vaporize.

Instead you use a resistor to limit the current and pull up the one side or bias it to 12v. The device your sending the signal to then looks to see if the voltage on that same wire is 12v or close to 0v when the reed switch closes pulling the voltage down to ground.

You have to be careful not to cause more current than the switch can handle to flow when it makes contact. I don't know what the limit is off hand and I don't expect to have time to figure it out.

Steve

 

[islandigital]

steve, Thanks for your very helpfull information. I found a few toyota test diagrams and in one it explains reed switches, It gave an example of 0.5v as an input, It did not dictate current. So off to the shack i go and im going to try to make up some sort of limiting device off the ignition +. Thanks alot for your help!!!!

BTW you never said what the DLC was? is that the connector on the cluster or where the ecu used to be? thansk again steve!!!!!!

 

[GVR4592]

Could you just use a 2g vss?

 

[steve]

Could you just use a 2g vss?

How do you drive the speedo if you put a 2G VSS in the trans?

DLC = Diagnostic Link Connector. The OBD 1 connector by your left foot.

 

[GVR4592]

How do you drive the speedo if you put a 2G VSS in the trans?

DLC = Diagnostic Link Connector. The OBD 1 connector by your left foot.

With hopes and dreams? I clearly wasn't thinking things through.